ARLINGTON — Lance Berkman was still trying to wrap his mind around the Roy Oswalt trade when the telephone rang at his ranch house in Mason a day later.

"This is going to sound a little callous," he remembers Astros general manager Ed Wade saying. "This isn't the way I want to do it, but we've got a time crunch."

Their conversation was brief and stunning. Even now, Berkman is attempting to comprehend that he's no longer playing for the Astros.

He looked around the visiting clubhouse here Tuesday night, to Derek Jeter and Mariano Rivera and the rest of his new Yankee teammates.

"I feel like an interloper," he whispered.

OK, back to the hours leading up to the end of his 12-year career with the Astros. Two days before the July 31 trading deadline, Wade told him there were eight teams interested in trading for him, and he needed to know which ones he'd consider going to.

Wade went down the list. Berkman said yes to the Yankees, Padres, Rays and Rangers, and no to the Giants, Angels, White Sox and Tigers.

Berkman hung up the phone and looked at his dad, Larry.

"I think I'm getting traded," he said.

He telephoned his wife, Cara, and then Andy Pettitte.

"It's just a surreal experience," he said. "I never thought I would be in that position, or it would be a reality. I never thought they'd trade Roy. When that happened, it was like a death in the family."

By the time he went to bed that night, he had begun to get excited. He'd been in a two-year slump, and at 34, seemed to be a shadow of the player he'd been during his first 10 seasons when he hit .302 and had a .413 on-base percentage. Two years ago, he would have been included in any discussion of baseball's best players.

He wondered if a change of scenery might get his career jump-started. By the time he fell asleep, "I was kind of excited about the possibilities. We're at a point in Houston where we're playing out the string, and we still have two months left. That's a tough thing for a veteran player. How do you motivate yourself for that long when you're not playing for anything?"

Wade telephoned him twice the next morning, once to say he had a deal pending with the Yankees and then to say it was done.

"He said he appreciated everything I'd done, and he was sorry we are where we are," Berkman said. "I said, 'I'm a big part of the reason why we're in this position. I haven't done my job."?'

Dreadful start for Yanks

He hasn't been any better with the Yankees than he was with the Astros. He entered Tuesday's game against the Rangers hitting .161 since the trade, and he was booed last weekend at Yankee Stadium.

"When you come to New York, it doesn't matter what you've done," he said. "You could have played in four World Series and been a .500 career hitter and drove in a thousand postseason runs. But unless you've done it in a Yankee uniform, the media is like, 'Well, we're not sure if this guy can really do it.'

"To have a good game against Boston (on Sunday), to get a hit to help us win that game, was good for me to establish a little bit of credibility or head in that direction. Then it's like, 'OK, maybe the 12 years in Houston are legitimatized.' There were 50 people at my locker when I hit A-Rod with that line drive (during batting practice). They were like accusing me of sabotaging the season. It's an edgier environment, and I thought it would give me a wakeup call or a kick in the pants."

Now about that two-year slump.

"I've had two injuries to my left leg," he said. "Talking to Kevin (Long, hitting coach), he said, 'Look, you're not using your legs in your swing like you used to.' They'd looked at video from 2006. I'm not using that back leg to drive through the ball like I normally would. I don't know if that's because I had the calf strain last season and then knee surgery this year. Part of me is like maybe that's it. Now I just have to work to get back to where I was."

As for the future, he simply has no idea. He'll be a free agent after the season, and while he would love to return to the Astros, he understands that may not be an option.

"I think this next two months will tell a lot about what I'm going to do in the future," he said. "It's no fun to stink. If it doesn't turn around, if things don't work out here and I don't hit, I think retiring is a real possibility."

Where am I?

He's still in a fog about it all. He went from hardly considering playing elsewhere to being on baseball's biggest stage.

"It's hard for me to look down at my uniform and not seeing Astros," he said. "I feel this is not real. And it may not sink in until the end of the season. It's funny. I still look at Houston on the scoreboard and think, 'What are we doing?' And then it's, 'Oh wait a minute, I'm not there anymore.'?"

richard.justice@chron.com